Light emitting device package and method for manufacturing the same

ABSTRACT

A light emitting device package capable of achieving an enhancement in light emission efficiency and a reduction in thermal resistance, and a method for manufacturing the same are disclosed. The method includes forming a mounting hole in a first substrate, forming through holes in a second substrate, forming a metal film in the through holes, forming at least one pair of metal layers on upper and lower surfaces of the second substrate such that the metal layers are electrically connected to the metal film, bonding the first substrate to the second substrate, and mounting at least one light emitting device in the mounting hole such that the light emitting device is electrically connected to the metal layers formed on the upper surface of the second substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of co-pending application Ser. No.11/706,251 filed Feb. 15, 2007, which claims the benefit of KoreanPatent Application No. 10-2006-0131732, filed on Dec. 21, 2006. Theentire contents of each of these applications are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light emitting device package and amethod for manufacturing the same, and more particularly, to a lightemitting device package capable of achieving an enhancement in lightemission efficiency and a reduction in thermal resistance, and a methodfor manufacturing the same.

2. Discussion of the Related Art

Light emitting diodes (LEDs) are well known as a semiconductor lightemitting device which converts current to light, to emit light. Since ared LED using GaAsP compound semiconductor was commercially available in1962, it has been used, together with a GaP:N-based green LED, as alight source in electronic apparatuses, for image display.

The wavelength of light emitted from such an LED depends on thesemiconductor material used to fabricate the LED. This is because thewavelength of the emitted light depends on the band gap of thesemiconductor material representing energy difference betweenvalence-band electrons and conduction-band electrons.

Gallium nitride (GaN) compound semiconductor has been highlighted in thefield of high-power electronic devices because it exhibits a highthermal stability and a wide band gap of 0.8 to 6.2 eV. One of thereasons why GaN compound semiconductor has been highlighted is that itis possible to fabricate a semiconductor layer capable of emittinggreen, blue, or white light, using GaN in combination with otherelements, for example, indium (In), aluminum (Al), etc.

Thus, it is possible to adjust the wavelength of light to be emitted,using GaN in combination with other appropriate elements. Accordingly,where GaN is used, it is possible to appropriately determine thematerials of a desired LED in accordance with the characteristics of theapparatus to which the LED is applied. For example, it is possible tofabricate a blue LED useful for optical recording or a white LED toreplace a glow lamp.

On the other hand, initially-developed green LEDs were fabricated usingGaP. Since GaP is an indirect transition material causing a degradationin efficiency, the green LEDs fabricated using this material cannotpractically produce light of pure green. By virtue of the recent successof growth of an InGaN thin film, however, it has been possible tofabricate a high-luminescent green LED.

By virtue of the above-mentioned advantages and other advantages ofGaN-based LEDs, the GaN-based LED market has rapidly grown. Also,techniques associated with GaN-based electro-optic devices have rapidlydeveloped since the GaN-based LEDs became commercially available in1994.

GaN-based LEDs have been developed to exhibit light emission efficiencysuperior over that of glow lamps. Currently, the efficiency of GaN-basedLEDs is substantially equal to that of fluorescent lamps. Thus, it isexpected that the GaN-based LED market will grow significantly.

By virtue of such technical development, the application of GaN-basedLEDs has been extended not only to display devices, but also to an LEDbacklight substituted for a cold cathode fluorescent lamp (CCFL) usedfor a backlight of a liquid crystal display (LCD) device, a white LEDlighting device usable as a substitute for a fluorescent lamp or a growlamp, and signal lamp.

Meanwhile, in addition to LEDs driven by DC power, high-voltage AC LEDchips, which can be driven even by general AC power, have also beendeveloped. For such an application, LEDs should exhibit a high operatingvoltage, a small drive current, a high light emission efficiency, and ahigh brightness at the same electric power.

Referring to FIG. 1, a structure of a general LED is illustrated. Asshown in FIG. 1, a buffer layer 2, an n-type semiconductor layer 3, anactive layer 4, and a p-type semiconductor layer 5 are sequentiallydeposited over a substrate 1 made of, for example, sapphire. Mesapatterning is then performed such that the n-type semiconductor layer 3is exposed. Thereafter, a current diffusion layer 6 is formed on thep-type semiconductor layer 5, as a transparent electrode having a highlight transmissivity.

For electrical connection of the LED to an external circuit, a p-typeelectrode 7 and an n-type electrode 8 are subsequently formed over thep-type semiconductor layer 5 and n-type semiconductor layer 3,respectively. Thus, an LED structure 10 is completely formed.

When a voltage from the external circuit is applied between the p-typeelectrode 7 and the n-type electrode 8 in the LED, holes and electronsenter the p-type electrode 7 and n-type electrode 8, respectively. Theholes and electrons are re-coupled in the active layer 4, so thatsurplus energy is converted into light which is, in turn, externallyemitted through the transparent electrode and substrate.

At this time, static electricity and a surge voltage may be applied tothe p-type electrode 7 and n-type electrode 8 electrically connected tothe external circuit, so that overcurrent may flow through the LEDstructure 10. In this case, the semiconductor is damaged, so that theLED can be no longer used.

In order to solve this problem, a voltage regulator is electricallyconnected to the LED. When overcurrent is generated, the voltageregulator bypasses the generated overcurrent, thereby preventing damageof the LED chip.

For such a voltage regulator, a zener diode using zener breakdown ismainly used. When a diode is fabricated to have a very high impurityconcentration, it has a space charge region width. In this case, astrong electric field is generated even at a small reverse voltage.

The strong electric field generated as above releases covalent bonds ofa lattice, thereby producing a number of free electrons and a number offree holes. As a result, an abrupt reverse current flows under thecondition in which there is little voltage variation. In accordance withsuch a zener diode function, it is possible to prevent damage of the LEDchip.

In an example of a conventional package using such a zener diode, acup-shaped curved portion is formed at a lead frame, and an LED isbonded to the curved portion of the lead frame. In this case, a voltageregulator such as a zener diode is bonded to another lead frame of thepackage. The lead frames are then wire-bonded to connect the voltageregulator and LED in parallel.

In the above-mentioned conventional method, there may be a degradationin electrical and optical characteristics and an increase in costsbecause it is necessary to form the cup-shaped curved portion, and toconnect the voltage regulator, which is separately prepared, using anoff chip method.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a light emittingdevice package and a method for manufacturing the same thatsubstantially obviate one or more problems due to limitations anddisadvantages of the related art.

An object of the present invention is to provide a light emitting devicepackage capable of achieving easy formation of a reflection film adaptedto forwardly reflect light laterally emitted from a light emittingdevice, achieving an enhancement in voltage withstand characteristics,and achieving easy external emission of heat through a ceramic orsilicon body exhibiting a superior thermal conductivity.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod for manufacturing a light emitting device package comprises:forming a mounting hole in a first substrate; forming through holes in asecond substrate; forming a metal film in the through holes; forming atleast one pair of metal layers on upper and lower surfaces of the secondsubstrate such that the metal layers are electrically connected to themetal film; bonding the first substrate to the second substrate; andmounting at least one light emitting device in the mounting hole suchthat the light emitting device is electrically connected to the metallayers formed on the upper surface of the second substrate.

In another aspect of the present invention, a light emitting devicepackage comprises: a first substrate having at least one pair of throughholes, and a metal film or a conductive film formed in each throughhole; a second substrate arranged on the first substrate, the secondsubstrate having a light emitting device mounting hole, and a reflectionfilm formed on a side wall surface of the mounting hole; firstelectrodes arranged between the first substrate and the secondsubstrate, each first electrode being connected to the metal film or theconductive film formed in an associated one of the through holes; and atleast one light emitting device arranged in the mounting hole, andelectrically connected to the first electrodes.

In another aspect of the present invention, a light emitting devicepackage comprises: a first substrate having a first surface, a secondsurface, and first and second electrodes respectively formed on thefirst and second surfaces and connected to each other; a secondsubstrate arranged on the first substrate, the second substrate having alight emitting device mounting hole, and a reflection film formed on aside wall surface of the mounting hole; and zener diodes eachelectrically connected, between one of the first and second substratesand an associated one of the first electrodes.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a sectional view illustrating an example of a general lightemitting device;

FIG. 2 is a perspective view illustrating a light emitting devicepackage according to a first embodiment of the present invention;

FIGS. 3 to 10 are sectional views illustrating the first embodiment ofthe present invention, in which:

FIG. 3 is a sectional view illustrating formation of a mask layer on anupper substrate;

FIG. 4 is a sectional view illustrating formation of a mounting hole;

FIG. 5 is a sectional view illustrating formation of a diffusion layer;

FIG. 6 is a sectional view illustrating formation of a reflection film;

FIG. 7 is a sectional view illustrating formation of through holes in alower substrate;

FIG. 8 is a sectional view illustrating formation of a metal film ineach through hole; and

FIG. 9 is a sectional view illustrating formation of a metal layer;

FIG. 10 is a sectional view illustrating the light emitting devicepackage according to the first embodiment of the present invention;

FIG. 11 is a sectional view illustrating an example of a method formounting a light emitting device;

FIG. 12 is a sectional view illustrating a state in which a plurality oflight emitting devices are mounted in the package according to the firstembodiment of the present invention;

FIG. 13 is a perspective view illustrating a light emitting devicepackage according to a second embodiment of the present invention;

FIG. 14 is a sectional view illustrating the light emitting devicepackage according to the second embodiment of the present invention;

FIG. 15 is a sectional view illustrating a state in which a plurality oflight emitting devices are mounted in the package according to thesecond embodiment of the present invention; and

FIG. 16 is a sectional view illustrating a light emitting device packageaccording to a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

The present invention may, however, be embodied in many alternate formsand should not be construed as limited to the embodiments set forthherein. Accordingly, while the invention is susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and will herein be described indetail. It should be understood, however, that there is no intent tolimit the invention to the particular forms disclosed, but on thecontrary, the invention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the invention asdefined by the claims.

Like numbers refer to like elements throughout the description of thefigures. In the drawings, the thickness of layers and regions areexaggerated for clarity.

It will be understood that when an element such as a layer, region orsubstrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may also bepresent. It will also be understood that if part of an element, such asa surface, is referred to as “inner,” it is farther to the outside ofthe device than other parts of the element.

In addition, relative terms, such as “beneath” and “overlies”, may beused herein to describe one layer's or region's relationship to anotherlayer or region as illustrated in the figures.

It will be understood that these terms are intended to encompassdifferent orientations of the device in addition to the orientationdepicted in the figures. Finally, the term “directly” means that thereare no intervening elements. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms.

These terms are only used to distinguish one region, layer or sectionfrom another region, layer or section. Thus, a first region, layer orsection discussed below could be termed a second region, layer orsection, and similarly, a second region, layer or section may be termeda first region, layer or section without departing from the teachings ofthe present invention.

First Embodiment

Referring to FIG. 2, a light emitting device package according to afirst embodiment of the present invention is illustrated. The lightemitting device package includes an upper substrate 100 and a lowersubstrate 200. A light emitting device 300 is mounted on the lowersubstrate 200. The lower substrate 200 is made of a material having aheat transfer coefficient. The upper substrate 100 is bonded to thelower substrate 200, and is provided with a reflection film forforwardly reflecting light emitted from the light emitting device 300.

The material of the lower substrate 200 may be ceramic such as SiC, AlN,or graphite having a high heat transfer coefficient. Here, the ceramicmeans a material such as an oxide, nitride, or carbide containingmineral elements as major components. Such a material, namely, theoxide, nitride or carbide, may be used for the lower substrate 200.

In addition, PCB, BeO, SiO, Si, Al, AlO_(x), PSG, a synthetic resin(plastic) material such as epoxy resin, ceramic or Al₂O₃ may be used.

The reason why the material having a high heat transfer coefficientshould be used is to rapidly transfer heat generated from the lightemitting device 300 to a heat sink, PCB, or metal core PCB (MCPCB). Itis preferable to use a material having a heat transfer coefficient of100 W/mk or more.

The upper substrate 100 may be made of semiconductor such as silicon(Si). In the upper substrate 100 made of such semiconductor, zenerdiodes may be formed in order to achieve an improvement in voltagewithstand characteristics.

Hereinafter, a process for manufacturing the light emitting devicepackage according to the first embodiment of the present invention willbe described.

First, a mask layer 110 for an etching process is formed to form amounting hole in the upper substrate 100.

For example, as shown in FIG. 3, a wet etch mask is formed over theupper substrate 100 which is made of silicon such that an anisotropicwet etch can be implemented for the upper substrate 100. Thereafter, thewet etch mask is removed from a region where the mounting hole 120 (FIG.4) will be formed, to expose a corresponding portion of the uppersubstrate 100. The mask layer 110 is then formed, as shown in FIG. 3.

Next, as shown in FIG. 4, a wet etch process is carried out, using anetching solution capable of anisotropically wet-etching silicon, suchthat a through hole is formed through the upper substrate 100. Thus, themounting hole 120 is formed. After the formation of the mounting hole120, the remaining mask layer 110 is completely removed.

Where the mounting hole 120 is formed in accordance with the anisotropicwet etch, the formation of the mounting hole 120 may be carried out suchthat the mounting hole has an inclined edge surface with a certaininclination angle θ, as shown in FIG. 4.

The inclination angle θ is an angle defined between the inclined surfaceof the mounting hole 120 and a bottom surface arranged beneath themounting hole 120 without being formed with the mounting hole 120. Theinclination angle θ may range from 35° to 70°.

The inclined surface will form a reflection surface for extraction oflight laterally emitted from the light emitting device which will besubsequently mounted. Accordingly, it is most theoretically preferredthat the inclination angle θ be 54.7°, taking into consideration thedistribution and direction of light horizontally emitted from the lightemitting device. However, practically, the inclination angle θ may rangefrom 50° to 60°.

Meanwhile, the light emitting device may have inclined side surfaces.Taking into consideration such conditions, the inclination angle θ ofthe mounting hole 120 may be determined to be within a range of 35° to70°.

Zener diodes may be formed in the upper surface 100 formed with themounting hole 120, in order to compensate for weak voltage withstandcharacteristics of the light emitting device. Hereinafter, a method forforming such zener diodes will be described.

In a certain region of the upper substrate 100, which is doped with animpurity in an appropriate concentration, an impurity having aconductivity opposite to that of the impurity doped in the uppersubstrate 100 is diffused to form a diffusion layer 131. Thus, zenerdiodes 130 (FIG. 5) are formed.

For such a selective impurity diffusion, as shown in FIG. 5, a diffusionmask 132 is first deposited over the upper substrate 100. Thereafter,the diffusion mask 132 is patterned, in order to enable the impurityhaving the conductivity type opposite to that of the upper substrate 100to penetrate into the upper substrate 100.

After the patterning enabling the selective diffusion of the impurity inthe upper substrate 100 through the diffusion mask 132, a diffusionprocess is carried out in an impurity diffusing furnace, to form thediffusion layer 131.

After completion of the diffusion process, the diffusion mask 132 isremoved, and an insulating layer is deposited over the upper surface100. Thereafter, a pad open process (not shown) may be carried out, toelectrically connect the zener diodes 130 to the external circuit.

After the formation of the diffusion layer 131 for forming the zenerdiodes 130, a reflection film 140 exhibiting a high reflectivity of 70%or more at wavelengths in a visible ray range, ultraviolet ray range,and infrared ray range is formed on the inner side wall surface(inclined surface) of the mounting hole 120, using Ag, Al, Mo, or Cr, inorder to enhance the reflectivity of the inner side wall surface.

Generally, metal thin films exhibit a high reflectivity, as compared toother materials, because they have unique metallic gloss. However, it isadvantageous to form a reflection film having a reflectivity of acertain value or more, in order to effectively externally guide lightemitted from the light emitting device.

The reflectivity of the reflection film 140 at wavelengths in a visibleray range, ultraviolet ray range, and infrared ray range may depend onthe material of the reflection film 140 and the formation method for thereflection film 140. However, it is possible to form the reflection film140, which has a reflectivity of 70% or more, by using a material suchas Ag, Al, Mo, or Cr, as described above, and a formation method whichwill be described hereinafter.

The reflection film 140 may be formed by depositing a metal thin filmusing a semiconductor process such as a sputtering process or anevaporation process, and patterning the metal thin film in accordancewith a photolithography process such that the metal thin film remainsonly in desired regions.

Alternatively, the photolithography process may be first carried out todeposit the reflection film 140. In this case, a lift-off process may besubsequently carried out. In accordance with another method, a seedmetal is deposited, and then patterned in accordance with aphotolithography process. A metal plating process is then carried outfor the pattered seed metal, to form the reflection film 140.

Thereafter, as shown in FIG. 7, through holes 210 is formed through thelower substrate 200, which is a ceramic substrate having a high heattransfer coefficient and a superior insulation property, using apunching technique or a laser machining technique.

For the ceramic material, which has a high heat transfer coefficient anda superior insulation property, AlN, SiC, graphite, etc. may be used. Itis preferable to use a ceramic material having a high heat transfercoefficient of 100 W/mk or more.

The through holes 210 may be formed in regions where the mounting hole120 of the upper substrate 100 is not positioned under the condition inwhich the upper substrate 100 and lower substrate 100 are bonded to eachother in an aligned state.

Alternatively, the through holes 210 may be formed in regions arrangedoutside a region where the light emitting device mounted to the uppersubstrate 100 will be bonded to the lower substrate 200, but arrangedwithin a region corresponding to the mounting hole 120.

Where the through holes 210 are formed outside the mounting hole 120, asdescribed above, they may be positioned such that dicing lines, alongwhich the package structure will be separated into unit packages,extends through the through holes 210. Alternatively, package dicing maybe carried out such that the through holes 210 are positioned inside thedicing lines.

The through holes 210 may have a vertical structure having a uniformcross-section (namely, the size of the through hole at the upper surfaceof the lower substrate 200 is identical to the size of the through holeat the lower surface of the lower substrate 200). Alternatively, thethrough holes 210 may have a vertical structure having a cross-sectionvarying such that the size of the through hole at the upper surface ofthe lower substrate 200 is larger or smaller than the size of thethrough hole at the lower surface of the lower substrate 200.

Subsequently, as shown in FIG. 8, a process for forming a metal film 220made of a metal or other conductive material on the through holes 210 iscarried out in accordance with a screen printing method or the like. Themetal film 220 may completely fill each through hole 210, or may coverthe inner surface of each through hole 210 in the form of a coating.

Thereafter, as shown in FIG. 9, metal layers are formed, as first andsecond electrodes 230 and 240, on a surface of the lower substrate 200,on which the light emitting device will be mounted, and a portion of thelower substrate 200 which will be electrically connected to the externalcircuit (not shown), respectively, are then patterned. For theconvenience of description, each metal layer connected to the lightemitting device will be referred to as a “first electrode 230”, whereaseach metal layer electrically connected to the external circuit will bereferred to as a “second electrode 240”.

Each first electrode 230 formed on the substrate portion, to which thelight emitting device is bonded, is made of a metal exhibiting a highreflectivity at wavelengths in a visible ray range, ultraviolet rayrange, and infrared ray range, namely, a metal such as Al, Ag, Cr, orMo. Accordingly, light downwardly emitted from the light emitting deviceand light downwardly reflected from various mediums arranged above thelight emitting device can be upwardly re-reflected. Thus, a furtherenhanced light extraction efficiency can be obtained.

After completion of the above-described processes for the uppersubstrate 100 and lower substrate 200, the upper substrate 100 and lowersubstrate 200 are bonded to each other in an aligned state. Thereafter,the light emitting device 300 is bonded to the mounting hole 120 of theupper substrate 100 such that the light emitting device 300 iselectrically connected to the first electrodes 230.

Where the light emitting device 300 has a vertical structure, namely,where the p-type electrode 310 and n-type electrode 320 are arranged atopposite surfaces, as shown in FIG. 11, the bonding of the lightemitting device 300 is achieved by attaching one surface of the lowerelectrode of the light emitting device 300 (for example, the p-typeelectrode 310) to one first electrode 230 formed on the lower substrate200, using a conductive epoxy resin 250, and electrically connecting theupper electrode of the light emitting device 300 (for example, then-type electrode 320) to the other first electrode 230 of the lowersubstrate 200 in accordance with a wire bonding process using a wire260.

On the other hand, where the light emitting device 300 has a horizontalstructure, the bonding of the light emitting device 300 is achieved bybonding the insulating substrate portion of the light emitting device300 to the first electrodes 230 of the lower substrate 200 or to theceramic substrate in accordance with a flip chip bonding method, andelectrically connecting the p-type electrode and n-type electrodearranged on the upper surface of the light emitting device 300 to thefirst electrodes 230 of the lower substrate 200 (not shown).

After the electrical connection of the light emitting device 300 to thefirst electrodes 230 of the lower substrate 200, a filler 400 such as atransparent epoxy resin or silicon gel may be filled in the mountingholes 120, in order to achieve an enhancement in light extractionefficiency.

On the other hand, when it is desired to change the wavelength of thelight emitted from the light emitting device 300, phosphors may becontained in the filler 400 which may be a transparent epoxy resin orsilicon gel.

For example, where a blue light emitting device is used for the lightemitting device 300, it is possible to realize emission of a white lightby adding yellow phosphors to the filler 400, and thus, enablinggeneration of a mixture of blue light and yellow light.

Although one light emitting device 300 may be mounted in the mountinghole 120, a plurality of light emitting devices 300, which emit light ofthe same color, may be mounted in the mounting hole 120, as shown inFIG. 12. Alternatively, light emitting devices, which emit red (R)light, green (G) light, and blue (B) light, respectively, may be mountedin the mounting hole 120, to realize a white light source.

Where a plurality of light emitting devices 300 are mounted, asdescribed above, a plurality of first electrodes 230 may be formed forthe mounting of the light emitting devices 300. A part of the pluralfirst electrodes 230 may be bonded, in common, to at least two of thelight emitting devices 300.

Thereafter, the package structure, which is formed by the uppersubstrate 100 and lower substrate 200 bonded to each other, as describedabove, is separated into individual packages. Thus, light emittingdevice packages are completely formed.

Meanwhile, the light emitting packages may be fabricated by separatingthe package structure including the substrates 100 and 200 intoindividual packages in accordance with a dicing process for mechanicalseparation of the substrates 100 and 200, and then bonding lightemitting devices 300 to the separated packages, respectively.

Second Embodiment

Referring to FIGS. 13 and 14, a light emitting device package accordingto a second embodiment of the present invention is illustrated. Thelight emitting device package includes an upper substrate 500 and alower substrate 600. A light emitting device 300 is mounted on the lowersubstrate 600. The upper substrate 500 is bonded to the lower substrate600, and is provided with a reflection film 510 for forwardly reflectinglight emitted from the light emitting device 300.

In the lower substrate 600, which may be a silicon substrate, zenerdiodes 610 are formed to achieve an improvement in the voltage withstandcharacteristics of the light emitting device 300.

A molding epoxy resin may be used for the upper substrate 500.

The upper substrate 500 or lower substrate 600 may be made of a materialselected from PCB, BeO, SiO, Si, Al, AlO_(x), PSG, a synthetic resin(plastic) material such as epoxy resin, ceramic, and Al₂O₃.

Through holes 620 may be formed through the lower substrate 600, using abulk micro machining technique or a dry etch method. FIG. 14 illustratesan embodiment in which the through holes 620 are formed using a wet etchprocess.

When the lower substrate 600 is subjected to a wet etch process atopposite sides of the lower substrate 600, through holes 620, which havean inclination, are formed at the opposite sides of the lower substrate600, as shown in FIG. 14.

When metal layers for formation of first electrodes 230 and secondelectrodes 240 are formed at the upper and lower ends of the throughholes 620, a metal film 220 is formed in each through hole 620. Thus,the first electrodes 230 and second electrodes 240 are electricallyconnected by the metal film 220.

Each first electrode 230, which is formed in a region where the lightemitting device 300 is bonded, is made of a metal exhibiting a highreflectivity at wavelengths in a visible ray range, ultraviolet rayrange, and infrared ray range, for example, a metal such as Al, Ag, Cr,or Mo. Accordingly, it is possible to effectively reflect light emittedfrom the light emitting device 300, and thus, to achieve an enhancementin light extraction efficiency.

The lower substrate 600 has superior heat transfer characteristics ofabout 140 W/mk. Also, the lower substrate 600, which can be subjected toa semiconductor process, can have a reduced height. Accordingly, it ispossible to achieve a reduction in thermal resistance.

Where the metal film 220 formed in each through hole 620 cannot exhibita desired conductivity, it may be possible to reduce the resistance ofthe metal film 220, using an electroplating method.

The process for forming the zener diodes 610 in the lower substrate 600may be identical to the process for forming the zener diodes 130 in theupper substrate 10 in the first embodiment. An impurity having aconductivity opposite to that of the lower substrate 600 is doped in thelower substrate 600, to form a diffusion layer 611.

As described above, the upper substrate 500 may be formed using amolding epoxy resin. When a mounting hole 520 is molded in the moldingprocess, the inclination of the edge surface of the mounting hole 520 isset such that light laterally emitted from the light emitting device 300can be forwardly reflected. A metal film having a high reflectivity isformed, as the reflection film 510, on the inner side wall surface (edgesurface) of the mounting hole 520, in order to achieve a maximumreflection efficiency.

After completion of the above-described process, the upper substrate 500and lower substrate 600 are bonded to each other in an aligned state.

Thereafter, the light emitting device 300 and first electrodes 230 areelectrically connected. A filler 700 may then be filled in the mountinghole 520, to which the light emitting device 300 is bonded, using atransparent epoxy resin or silicon gel. Of course, phosphors may becontained in the filler 700, as in the first embodiment.

A plurality of light emitting devices 300, which emit light of the samecolor, may be mounted, as shown in FIG. 15, in order to achieve anenhancement in light power. Alternatively, light emitting devices 300,which emit red (R) light, green (G) light, and blue (B) light,respectively, may be mounted, to realize a white light source.

The remaining configurations of the second embodiment may be identicalto those of the first embodiment, and so, no description thereof will begiven.

Third Embodiment

Referring to FIG. 16, a light emitting device package according to athird embodiment of the present invention is illustrated. The lightemitting device package includes an upper substrate 500 and a lowersubstrate 600. The lower substrate 600 is made of semiconductor such assilicon, and is formed with through holes 620 each having an inclinationin one direction. The upper substrate 500 is formed with a mounting hole520 for mounting a light emitting device 300.

The upper substrate 500 or lower substrate 600 may be made of a materialselected from PCB, BeO, SiO, Si, Al, AlO_(x), PSG, a synthetic resin(plastic) material such as epoxy resin, ceramic, and Al₂O₃.

A reflection film 511 is formed around the light emitting device 300.The reflection film 511 may extend along the inner side wall surface ofthe mounting hole 520 and the surface of the mounting hole 520 where thelight emitting device 300 is mounted.

Each through hole 620 of the lower substrate 600 can be formed to havean inclination in a certain direction, in accordance with a wet etchprocess carried out in the direction. A metal film 220 is formed in eachthrough hole 620.

FIG. 16 illustrates the case in which the light emitting device 300 hasa vertical structure. As described above, current is applied, via thelower electrode 310 and upper electrode 320, to the light emittingdevice 300, which has a vertical structure.

The light emitting device 300 may include a support layer 330. In thiscase, the support layer 330 may be attached to one of the firstelectrodes 230, using a conductive epoxy resin 250.

Where the light emitting device 300 is formed on the support layer 330,the lower electrode 310 of the light emitting device 300 may include anohmic electrode, and a reflection electrode arranged beneath the ohmicelectrode. If necessary, a reflection electrode having ohmiccharacteristics (NiAg or NiAu-based reflection electrode) may be used.

The remaining configurations of the third embodiment may be identical tothose of the first and second embodiments, and so, no descriptionthereof will be given.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A light emitting device package, comprising: a substrate comprising afirst surface, a second surface, and a through hole, wherein the throughhole has an inclination with respect to a vertical direction to thefirst surface, and wherein the through hole is inclined to at least onedirection; a first electrode on the first surface, wherein the firstelectrode has a pair of portions; a light emitting device on the firstsurface, wherein the light emitting device is arranged on the pair ofportions, wherein the first electrode is electrically connected to thelight emitting device; a second electrode on the second surface, thesecond electrode electrically connected to the first electrode via thethrough hole; a zener diode electrically connected to the firstelectrode, wherein the zener diode is arranged adjacent to the lightemitting device; and an encapsulation on the light emitting device. 2.The light emitting device package according to claim 1, wherein thezener diode comprises: a semiconductor layer; and a diffusion region onthe semiconductor layer.
 3. The light emitting device package accordingto claim 2, wherein the semiconductor layer has a first conductivity andthe diffusion region has a second conductivity that is opposite to thefirst conductivity.
 4. The light emitting device package according toclaim 1, wherein the substrate comprises at least one material of PCB,BeO, SiO, Si, Al, AlO_(x), PSG, a synthetic resin material, ceramic, andAl₂O₃.
 5. The light emitting device package according to claim 1,wherein the zener diode is laterally arranged with respect to thethrough hole.
 6. The light emitting device package according to claim 1,wherein the through hole is inclined to two directions.
 7. The lightemitting device package according to claim 1, further comprising: aphosphor material arranged on the light emitting device.
 8. The lightemitting device package according to claim 1, wherein the encapsulationcontains a phosphor material.
 9. The light emitting device packageaccording to claim 8, wherein the phosphor material comprises a yellowphosphor material.
 10. The light emitting device package according toclaim 1, wherein the substrate has a heat transfer coefficient of 140W/mK or more.
 11. The light emitting device package according to claim1, wherein the light emitting device is bonded to the first electrodewith a conductive material.
 12. The light emitting device packageaccording to claim 1, wherein the second electrode is electricallyconnected to the first electrode via a metal or a conductive materialarranged in the through hole.
 13. The light emitting device packageaccording to claim 12, wherein the through hole is partially filled withthe metal or the conductive material.
 14. The light emitting devicepackage according to claim 1, wherein the light emitting device is on acenter of the first surface.
 15. The light emitting device packageaccording to claim 1, wherein the first electrode comprises a metalhaving high reflectivity in at least one wavelength range of visiblelight, ultraviolet light, and infrared light.
 16. The light emittingdevice package according to claim 1, wherein the first electrodecomprises at least one of Al, Ag, Cr, and Mo.
 17. The light emittingdevice package according to claim 1, wherein the encapsulation comprisesepoxy or silicone.
 18. The light emitting device package according toclaim 1, wherein at least one of the second electrode and the throughhole comprises a pair of portions.
 19. The light emitting device packageaccording to claim 18, wherein a shortest distance between the lightemitting device and the zener diode is shorter than a shortest distancebetween the pair of portions of the through hole.
 20. The light emittingdevice package according to claim 18, wherein the pair of portions ofthe first electrode and the pair of portions of the second electrode areconnected via a metal or a conductive material arranged in the pair ofportions of the through hole.
 21. The light emitting device packageaccording to claim 1, wherein the substrate has a rectangularparallelepiped shape.
 22. The light emitting device package according toclaim 1, wherein the first electrode and the second electrode contactthe through hole.
 23. The light emitting device package according toclaim 1, wherein the first electrode is connected to the light emittingdevice via a conductive bonding material.
 24. The light emitting devicepackage according to claim 1, wherein the first electrode covers thefirst surface.
 25. The light emitting device package according to claim1, wherein the light emitting device is on a first portion of the firstelectrode and the zener diode is on a second portion of the firstelectrode
 26. The light emitting device package according to claim 18,wherein widths of the pair of portions of the second electrode aresubstantially the same.